The proposed research will examine the structure and measurement of wives' and husbands' responses about their social experiences, subjective child utility, family size norms, and fertility desires and expectations. Comparisons of the structure and measurement of these responses will be made between couples in different social groups. The primary structural variation of interest is whether wives' and husbands' responses are multiple indicators of a single couple variable or indicators of separate wife and husband variables, respectively. In addition, four variations in measurement properties of those responses will be examined: equality of true variances of wives' and husbands' responses; equality of error variances of wives' and husbands' responses; equal reliability of wives' and husbands' responses; and correlations between response errors of wives and husbands. Analyses will be based on responses of 873 wives and their husbands who participated in a Wisconsin survey of young adults' social role definitions and fertility orientations during 1972-73. Maximum likelihood methods will be used to estimate models with different structure and measurement and to test their goodness-of-fit to the observed covariances. Tests of the equality of structural or measurement parameters for couples in different social groups will also be made within this analytic framework. The results of this research will provide a basis for evaluating the findings of earlier research on fertility decisions and behavior, which may have been based on faulty assumptions about the measurement and structure of wife and husband responses. A general theory of response error in the analysis of data from married couples will also be derived from this research. Finally, couple group differences in the structure of wife and husband responses may suggest alternative explanations of marital fertility decisions and behavior among couples in different social groups.